Education of the republic of uzbekistan tashkent state technical university named after islam karimov

FACTORS AFFECTING THE COEFFICIENT OF ADHESION OF MATERIALS 
AND MATERIALS.
Two contact surfaces or contact spots are formed where the wheel rests on the rail. As 
can be seen from Figure 1, the contact spot of the wheel is convex and the stain of the rail is 
concave. 
 
Figure -1. The direction of movement of the contact spot and the fibers under the 
influence of the vertical force load of the wheel 
The arrows indicate the directions of fiber displacement at the wheel and rail contact 
points that accompany the loading process under the influence of the vertical force R of the 
wheel. The lines of the contact spots have a complex appearance, depending on the shape of the 
bandage and rail head surfaces, which vary depending on the degree of rupture. Therefore, in the 
theoretical study of the phenomena that occur when the wheel rolls along the rails, the contact 
spot can be seen as a flat band of width h, in which case the load from the wheel pair to the rails 
т
P
23
18
0


,equals 
мм
h
26

[5]. 
In the flat scheme shown in Figure 2, the contact spots are presented in the form of 
straight line sections: - for the wheel and - for the rails. In imagining the contact spot in the form 
of an absolutely smooth surface band, the vertical load on the spot results in normal specific 
loads with an elliptical semicircular shape. In fact, the surfaces that touch each other are not 
absolutely flat, and the actual contact area is only a small part of the contour surface of the 
contact spot (approximately 10%). The normal pressures that occur in this case are so large that 

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the deformations take the form of a flexible plastic with a relatively complex stress diagram, and 
intermolecular gravitational forces apply between the actual contact elements. 
The torque applied to a pair of wheels 
к
М
 
under the influence, the contact spots tend to 
slide relative to each other. In this case, the intermolecular gravitational forces resist 
displacement, resulting in tensile stresses. 
These stresses, in turn, form the coupling force S applied to the wheel contact point and 
its equivalent, as well as the oppositely applied force. 
By its physical nature, the coupling force is one of the manifestations of dry frictional 
force, which occurs during the rolling of the wheel along the rails. Recent studies by local 
scientists [1-5], as well as abroad [8-12] allow us to understand the physical nature of the 
processes that occur during dry friction, as well as to explain the laws of changes in the force of 
contact of the wheel with the rail.